The invention relates to a guide section for axial guidance of a slide for a power tool having an axial toothed rack for longitudinal feed.
This type of guide section with an axial toothed rack is used in particular for drilling rods and guide rails when working rock, for example for core drilling and stone saws. In order to be able to sustain the high flexural torsional moments that occur and at the same time to remain transportable at a length of up to several meters, the guide sections must be configured out of high-rigidity hollow sections of extruded aluminum or aluminum alloy.
According to DE 4326194 a toothed rack is configured in one piece with the guide section. By virtue of the lower strength relative to steel, an equivalently stressable rail had to be formed wider in the case of aluminum sections, whereby consequently wider toothed rack drives were required.
According to U.S. Pat. No. 5,549,390 a guide section of a guide rail for a drilling tool in configured of a highly rigid hollow section with a toothed rack of rectangular cross-section arranged in a rectangular receiving groove. According to DE 19749625 a guide section configured as a highly rigid hollow section made of extruded aluminum has a wedge-shaped, expanded receiving groove for a toothed rack. The toothed rack must be fastened by means of separate fastening members in the receiving groove. The fastening bore holes extending through the toothed rack weaken its strength, whereby breakage is more probable.
According to U.S. Pat. No. 5,845,996, a rack is fastened using several screws and nuts in an undercut fastening groove of a guide section formed of a highly rigid hollow aluminum section. Drilling of the toothed rack and the guide section and subsequent tightening is technologically costly and the number of required components is appreciably increased by the screws and nuts.